Types Statement Summary

Types is a nonterminal metalanguage statement that initiates the definition of the low level data types to be used by the parser. gmBasic has highly optimized retrieval algorithms that restrict the number of simultaneous retrieval sequences that can be occurring. The lowest level component of the compiler is the parser that converts the individual lexemes, the actual words and punctuation marks, in the source statements into token type, lexeme pairs. Tokens are language independent codes that identify the actual roles of lexemes. To do the parse gmBasic needs to do a retrieval that takes a lexeme and looks up its token type. A separate simple data type is needed to do this retrieval so that the low level parsing operation is guaranteed not to interfere with the higher level symbol table retrievals being performed by the compiler. This data type is referred to as a "standard list" which contains a simple collection of name, integer value pairs. The Types statement creates a set of standard lists that contain these lists of information needed by the parser. They are as follows:

The Types statement has no attributes.

The substatements of the Types statement are as follows:

Type Substatement Summary

Type is a terminal, or nonterminal metalanguage substatement that occurs within the Types statement. Both forms of the statement add an entry to the list of basic binary types recognized in the metalanguage. The nonterminal form adds a secondary list to the type.

The attributes of the Type statement are as follows:

If the statement is not terminal it introduces a secondary list that is accessible via the name. The substatements of the Type statement are as follows:

The attributes of the Entry statement are as follows:

The script errors associated with the Type statement are as follows: